Trematodes 2010 - Introduction Digenetic Trematodes have A...

1DIGENETIC TREMATODESDwight D. BowmanIntroductionDigenetic Trematodes haveA solid bodyCovered with a syncytium, the tegument, rather than a ciliated ith liepitheliumAn excretory system composed of flame cells Are typically hermaphroditicHave separate ovaries and testesOviduct and vas deference have separate terminations, but usually in the same pore or genital openingCapable sometimes of self fertilization, but usually pair with another trematode of the same speciesTypically bear two suckers, an anterior sucker around the mouth dtikth t illtidb dand a posterior sucker that is usually at midbodyOviduct, typically filled with eggsEggs very often operculateYolk cells are typically separate from the ovum within the eggshellEgg shell is often brown in colorIntroductionA vertebrate final hostA mollusk, intermediate hostAsexual multiplication in the mollusk (usually a snail)Snails infected by the stage from the egg, a ciliated miracidiumIn snail have various developmental stagesMother sporocystDaughter sporocystRediaUltimately producing cercarial stages that are infective to the vertebrate final hostNo multiplication occurs in the vertebrate host

This
preview
has intentionally blurred sections.
Sign up to view the full version.

2General Life CycleIt was in 1845, that JJS Steenstrup showed that the stages in the snail were the same as those found in the vertebrateShowed that had asexual multiplication in the snailsCalled the multiplication through two different stages the alternation of generationsstages the alternation of generations THE EGGEMBRYONATED EGG

3MIRACIDIUMPENETRATING A SNAIL

This
preview
has intentionally blurred sections.
Sign up to view the full version.